Many service providers, services, applications or devices require authentication of users who may attempt to access services or applications remotely from, for example, a mobile device such as a smart phone, a tablet computer, a mobile health monitor, or other type of computing device. In some contexts, a service provider such as a bank, a credit card provider, a utility, a medical service provider, a vendor, a social network, a service, an application, or another participant may require verification that a user is indeed who the user claims to be. In other contexts, a service provider may merely require verification that a user is really a human person, and not an automated computer 'bot, before accepting an inquiry from the user. With a growing number of sensors on mobile devices including biometric sensors such as fingerprint sensors, pulse detectors or iris scanners, contextual sensors, location sensors, video cameras and microphones, users may wish to limit or control the quantity and type of sensor data that is shared.
Similarly, the user may wish to validate a service provider, service, application, device or another participant before engaging in a communication, sharing information, or requesting a transaction. The user may desire verification more than once in a session, and wish some control and privacy before sharing or providing certain types of personal information. Furthermore, a user may wish to negotiate with a service, an application, or another participant before transmitting requested personal information.